Advice on the BS degree that would best compliment grad school interests.

At the moment I am planning to pursue a bachelors with the end goal of obtaining a masters and potentially a PhD in either the areas of Geophysics, Planetary science, or maybe even Astrobiology. The University I would be attending for the BS degree does offer a BS in Geology and Geophysics, but I was wondering if I should be considering a BS in Physics instead?

The main reason I would consider the physics degree is because it would appear to offer more flexibility in the event I would prefer to go in another direction for graduate school (ie engineering, etc). However it would seem that the geo course work, field training, and research would be most beneficial if I do continue down my intended path.

Anyone with experience in these fields or related fields that could offer some advice?

Maybe major in physics and then minor in whatever you're interested in. Also, a math minor will most likely help you in whatever field of physics you go into. There's also the possibility of double majoring too...